Fire extinguishing method and apparatus



June 29, 1943. H. v. WILLIAMSON ETAL 2,

FIRE EXTINGUISHING METHOD AND APPARATUS Filed March 24, 1942 i )2 l I II I I I I l I I I I I I I l 3 )3 Mia/5111mm *1 Patented June 29,1943

FIRE EXTINGUISHING METHOD AND APPARATUS Hiidlng V. Williamson and WalterF. Mitcheltree,

Chicago, Ill., assignors, by mesne assignments,

to Reconstruction Finance Corporation, Chie cago, Ill., a corporation ofthe United States Application March 24, 1942, Serial No. 436,052

Claims.

This invention relates toa method of employing liquid carbon dioxide forextinguishing fires involving enclosures in which certain treatment orprocess steps, requiring the use of inflammable substances, areperformed, and apparatus suitable for carrying out said method.

It is the present practicein numerous industries to subject certainmaterials, objects, parts, or the like, to one or more process ortreatment steps in relatively small enclosures or booths which usuallyhave one wall, or a sizable portion thereof, omitted to provide apermanent opening. These process or treatment steps very often involvethe use of highly inflammable fluids, powders, gases, or the like. Forthat reason, fires are rather easily started and they usually are ofsuch a size that theentire interior of the enclosures is involved. Thepermanent opening left in each of these enclosures, the readilydisplaceable character of the inflammable .substances employed, and thesize or extent of the are diiilcult to overcome.

If the aforementioned treatment or process;

steps were carried out in a completely or' substantially completelyclosed off space it would be a comparatively simple matter to flood thesame with suflicient carbon dioxide to provide the necessaryextinguishing concentration. The provision of a permanent opening,however, allows the extinguishing vapors to escape at such a rapid ratethat total flooding of the space in the customary manner can only beaccomplished by delivering the vapors at a very rapid rate; i. e., alarge volume at a high velocity. This type of discharge of carbondioxide creates such a powerful blast or draft in the comparativelysmall enclosure that the flames are blown out through the opening to adistance of several feet. Also, some of the flaming treatment substanceoccasionally is dislodged and blown through the opening. Naturally,these conditions are very objectionable and may result in spreading thetire to other portions of the building in which the treatment enclosureor booth is located.

Starting with the above premise in mind, experiments were carried out todetermine whether extinguishment could be accomplished by dischargingthe carbon dioxide in such a manner as to simultaneously provide ascreen or barrier for the opening and build up the desired concentrationwithin the enclosure. Pipe sections having one or more rows of closelypositioned discharge orifices or regular commercial room floodingnozzles were employed for these tests. The pipe charge, or during theperiod before the liquid sections were located either at the top or atthe two side margins of the opening with the orifices or nozzlespointing into the enclosure and/or across the area of the opening.

The positioning of any of the above noted pipe sections along the topmargin of the opening proved to be the least eflective while positioningsuch pipes along the opposite side margins provided fairly satisfactoryresults. Some of the tests employing top marginal pipes failed to eflectcomplete extinguishment because of low,

non-uniform concentration of the extinguishing medium. The highestconcentration produced by any of these tests was forty percent while theaverage was approximately twenty-seven percent. The best extinguishmenttime that could be obtained was ten seconds while the average time wastwenty-eight seconds.

No one of these discharge arrangements provided perfect screening forthe opening of the enclosure. The top marginal arrangements that failedto effect complete extlnguishment caused flames to be blown through theopening during the entire period of discharge or the extinguishingmedium. The more favorable tests caused flames to be blown through theopening to distances ranging from ten feet to fifteen feet duringapproximately the first half of their extinguishment time, or until thefire had partially subsided. The most pronounced blowing was found tooccur during the first few seconds of discarbon dioxide reached theorifices or nozzles and when nothing but vapors were being discharged.This delay in the arrival of liquid carbon dioxide at the region ofrelease or dis--. charge is a normal characteristic of carbon dioxideand this initial delay period varies depending on the length of the flowpath from the source of supply to the region of release as well as suchother factors as the total discharge area provided by the releaseorifice or orifices. After the liquid reached the orifices or nozzlesand was released to create a more dense discharge that was formed ofmixed snow and vapors, the blow- 2 asaavos medium both into theenclosure and across the the side of the enclosure or booth in which itis entire area of the opening. located.

3. The more dense the discharge that produces the screen or barrier forthe opening, the less the blowing of flames through the opening.

4. Blowing flames through the opening cannot be prevented if asubstantial amount of the extinguishing medium is discharged into theenclosure prior to the development of a dense screen or barrier acrossthe entire area of the opening.

The primary object of this invention is to.v

provide a method and apparatus. for employing carbon dioxide toeffectively extinguish fires involving partially open enclosures orbooths in which are carried out process or treatment steps that requiretheuse of highly inflammable materials.

A further important object of the invention is the provision of a methodand apparatus of the above mentioned type.which will discharge theextinguishing medium from opposite margins of the enclosure opening;which will create a high concentration of carbon dioxide in theenclosure; which will provide a dense screen or barrier across theentire area of the enclosure opening, and which will produce theaforesaid dense screen or barrierprior to discharging a substantialamount of the extinguishing medium into the enclosure.

Positioned at the opposite side margins of the opening 6 are the twovertically arranged discharge devices 'I. These devices are-ofsuflicient length to extend the full height of the opening. A supplyline 8 extends from any suitable source of supply of liquid carbondioxide, such as the bulk storage tank of Patent No. 2,143,311, issuedto EricGeertz, January 10, 1939, or a bank of high pressure cylinders.This supply line 8 is connected by means of the branch lines 9 to thedischarge devices I for supplying, these devices with the requiredamount of liquid carbon dioxide. Naturally, .any suitable form ofautomatic or manual control mechanism may be connected in the supplyline I to determine the time and duration of discharge periods.

The construction of each one of the discharge devices I will bedescribed in detail in connection with the disclosures provided by Figs.3 and 4.

. Each one of these devices includes a discharge pipe l0 which isconnected at its upper end to one of the branch pipes 9 andis threadedat its lower end into a combined cap and fioor anchor .II. This elementll may be embedded in a concrete' fioor or otherwise suitably anchoredto prevent movement of the device during discharge of Still anotherobject of the invention is the provision of a method and apparatus forcreating a screen or barrier across an open area while building up ahigh fire extinguishing concentration on one side thereof.

Other objects and advantages of the invention will be apparent duringthe course of the following description.

In the accompanying drawing forming a part of this specification and inwhich like numerals are employed to designate like parts throughout thesame, a 1

- Figure 1 is a vertical sectional view of an enclosure, taken on linell of Fig. 2, and showing the fire extinguishing apparatus embodyingthis invention in elevation and as viewed from within the enclosure,

Figure 2 is a horizontal sectional view taken through the enclosureandshows the flire extinguishing apparatus in top plan, I

Figure 3 is an enlarged. fragmentary view of one of the dischargedevices shown in position this invention, and first particularlyreferring to Figs. 1 and 2, the reference character 5 is employed todesignate in a general way an enclosure or booth in which certaintreatment or process steps, involving the use of highly inflammablesubstances, are carried out. This enclosure or booth is provided with apermanent opening 6 in one wall thereof. It is to be understood thatthis illustration of an enclosure or booth is only representative and isnot intended to restrict the invention to any particular proportions ordimensions. Additionally, while the permanent opening 6 is shown asextending the full width of the enclosure or booth 5, it is to beunderstood that the permanent opening need not correspond in eitherhorizontal or vertical dimensions with one side of the enclosure orbooth.

That is to say, the opening may be smaller than the carbon dioxide. Atsuitably spaced intervals -the discharge pipe is provided with the well'known Camus type of discharge orifice II. The counter-bored orre-entering formation of these orifices prevents them from plugging upwith snow when the carbon dioxide is discharged therethrough.

A merging and segregating chamber I3 is pro vided for the discharge pipeI 0 and is arranged to enclose the latter throughout its length. or

throughout the length of the pipe that corresponds with the height ofthe opening 6. By inspecting the sectional view of-Fig. 4, it will beseen that this chamber is substantially of halfheart shape. The twolongitudinal edges l4 and I5 terminate in spaced relation to each otherto provide a discharge openingwhich extends the length of the chamber.The opposite ends of the chamber are closed by the walls I6 which arewelded in place in any suitable manner.

Forthe purpose of anchoring the discharge pipe III to the edge portionll of the chamber and to brace and reinforce the chamber and itsdischarge opening throughout their length, straps I! are provided. Thesestraps are each fastened at one end by a screw 1 8 which passes throughthe strap, the edge portion ll of the chamber l3 and the discharge pipeIII with the screw being threaded into the opening formed in the pipe.The remainingend of each strap is anchored to the edge portion l5 of thechamber l3 by a bolt and nut assembly l9; Suitable lock washers 2!- areprovided for both of these types of securing elements I 8 and I9 toprevent loosening of the same.

In circumferential alignment with each one of deflectors which guide theextinguishing medium to and through the slots or openings.

By again inspecting Fig. 4, it will be seen that the cross sectionalshape of the chamber I 3 provides an inner surface 23 ,which is curvedthroughout the circumferential extent of the chamber. That is to say,the inner surface 23 of the chamber wall is curved transversely of thechamber. This figure also shows the longitudinal series of orifices i2as pointing or facing in the direction of the curved surface 23 of thechamber so as to intersect the latter relatively close .to the edge llof the chamber. The longitudinal series of discharge slots or openings22, with their struck-in tongues 2|, are arranged relatively close tothe longitudinal edge l of the chamber wall. It willbe seen, therefore,that.

any material which is discharged from the pipe ll through the series oforifices I2 will be compelled to travel along the interior curvedsurface 23 of the chamber to reach the discharge opening that is definedby the chamber edges i4 and I5 and this material, therefore, will becompelled to partake of curvilinear motion instead of the straight linemotion that will exist between each one of the orifices l2 and theopposing zone of the internal curved surface 23 of the chamber. That isto say, the curved surface of the cham her will deflect the dischargedmedium from its straight line path of movement and will force the mediumto flow through a curved path until it arrives at the longitudinaldischarge opening of the chamber. Because the interior of the chambet isnot obstructed throughout its length, the extinguishing mediumdischarged through the several orifices l2 will be permitted to spreadlongitudinally of the chamber and merge into a continuous mass beforearriving at the discharge opening of the chamber.

By comparing the disclosure of .Fig. 4 with the disclosure of Fig. 2, itwill be seen that each discharge device is arranged so that its chamberdischarge opening faces or points across the area of the opening 6 forthe enclosure or booth 5. Therefore, the extinguishing medium that isexpelled through the two chamber openings will travel across theenclosure opening 6 to meet at approximately the vertical medial line ofthis opening. The extinguishing medium discharged from the two devicesI, therefore, will provide a screen or barrier that will completelyclose off the opening 6 of the enclosure or booth 5. A comparison ofthese last two mentioned figures also shows that the two dischargedevices are arranged so that any material which is released through thelongitudinal series of openings or slots 22 will be directed into theenclosure or booth 5 inwardly of the screen or barrier that is providedby the maindischarges from the two devices I.

The mode of operationof this fire extinguishing apparatus now will bedescribed. Liquid carbon dioxide is delivered to the discharge pipes illof the two devices I by means of the main pipe line 8 and its twobranches 9. This liquid is released through the orifices l2 and, as aresult of this sudden expansion of the liquid and the accompanying dropin pressure, the jets or streams of liquid carbon dioxide will beimmediately converted to mixtures of snow and vapors. The Jets of snowand vapor released from the orifices I2 will partake of straight linemotion until they arrive at the opposed zones of the interior curvedsurface of the associated chamber it. The mixture will then be compelledto partake of ourvilinear. motion as a result of flowing over thechamber surface 23. Because the snow portion of the mixture is manytimes more dense than the vapor portion, centrifugal force will compelthe snow to seek the outer portion of the curvi linear path, or to forceits way toward the curved surface 23. As a result of this movement ofthe snow particles, the vapors arecrowded or forced away from the curvedsurface 23, or away from the peripheral margin of thecurvilinear path.

Therefore, by the time the snow and vapors reach the discharge openingof the chamber II, the snow has formed a layer that lies adjacent theinner surface of the chamber while the vapors form a layer that issuperimposed with respect 'to the snow layer, or which lies closer tothe longitudinal axis of the chamber. The final di charge through theopening of the chamber, which is defined by the longitudinal edges Itand i5, has its snow segregated in one layer and its vapors segregatedin another layer. Due to the arrangement of the discharge devicesl withrespect to the opening 6 of the enclosure or booth 5, the vapor layer ofeach discharge will be erv ranged on the outer side of the stream whilethe snow layer will be arranged on the inner side. 1 The vapor layers ofthe two opposed discharges, therefore, will shield the snow layers fromthe atmosphere outside of the enclosure opening 5.

These two opposed streams will be equal in width to the length of each.chamber is or to the height of the enclosure opening 6. The thicknessof each one of these two streams will correspond with the combinedthickness of the layers of segregated snow and vapors discharged by eachdevice I. These two wide and relatively thin streams will meet orimpinge against each other at approximately the vertical medial line ofthe enclosure opening 8 to provide a continuous, dense screen or barrieracross the entire area of this opening. As these two streams'will travelin the same vertical plane, their impingement will cause the materialsof the two streams to be deflected in opposite horizontal directions.That is to say, each stream will be split along a vertical line so thatone part of the stream will flow or be deflected into the enclosure orbooth 5 while the other portion will be deflected outwardly. Thisvertical line of cleavage will be located approximately at the regionwhere the snow layer blends into' the vapor layer with the result thatthe snow particles will be deflected into the enclosure or booth 5 whilethe vapors will be deflected outwardly to create a cloud in front of theopening 5.

'By the time the discharges from the several orifices [2 have traveledover the curved surfaces 23 of the chambers I! from the points of firstcontact with this surface to the locations of the tongues 2i andopenings or slots 22, the snow and vapors have been segregated to aconsiderable extent. The tongues 2| will terminate within the depth ofthe snow layer and, therefore, will function to scoop or deflect snowoutwardly through the openings or slots 22 into the interior of theenclosure or booth I. The snow discharged through the openings or slots22 and the snow snow of both of these streams into layers will provide avery dense screen or barrier for the opening.

In the introductory portion of this specification the statement is madethat a considerable amount of the extinguishing medium should not bedischarged into the enclosure or booth prior the creation of a densescreen'or barrier across the opening of the enclosure or blowingoi'jfiame through the opening would result. Thisjstatement had referenceto the initial period of discharge when nothing but carbon dioxidevaporsare discharged by the devices I, prior to the arrival of liquid carbondioxide in substantial amounts at the discharge orifices l2. Thisdesired result is obtained with the discharge devices 1 notwithstandingthe provision oi the slots or openings 22 and the tongues 2|. Whennothing but vapors are being discharged through the orifices l2, thevolume of flow is not as great as when liquid is released through theorifices it. Therefore, the density. per unit of volume, of the materialflowing through the chamber I3 is not as great. Additionally, thedensity of the vapors is not of such a value as to compel the vapors tocrowd or pack tightly against the inner curved surface 23 of the chamberi 3. A a result of these two factors, a comparatively small amount ofcarbon dioxide vapors will be discharged into .the interior of theenclosure or booth 5 during this initial period. of discharge of thecarbon dioxide vapors. After the liquid reaches the orificesv l2, therelease of the same through the orifices will provide snow as well asvapors and the screen or barrier formed across the opening 6 of theenclosure will 'be suillciently dense to permit a greater volume ofcarbon dioxide to be expelled into the enclosure or booth.

Extensive tests carried on with the discharge apparatus of thisinvention clearly prove its ei-' fectiveness to completely extinguishfires involving the highly inflammable substances that are used in thesetreatment or process enclosures or booths. No blowing of flames throughthe opening 6 occur during the entire extinguishment period. Carbondioxide fire extinguishing concentrations of forty-five percent or morecan be created within the enclosure or booth I with this apparatus.Fires involving the entire 111- terior of the enclosure or booth havebeen extinguished in as short a time as four seconds. The averageextinguishment time for all of the tests conducted with this apparatuswas seven seconds. By comparing the figures obtained from the tests madewith this apparatus with the figures obtained during the testsintroduction of this specification, it will be seen that considerablyimproved extinguishment is provided.

Although the disclosure given above specifically referred to theextinguishment of fires involving partially'open processing enclosuresor booths, persons skilled in the art to which this invention relateswill readily appreciate that the method and apparatus can be employedjust as effectively to provide screens or barriers for the openings ofother types of enclosures while building,

upa fire extinguishing concentration in the latter and that themethodand apparatus can even be employed for creating a screen or barrieracross the entire area of a tunnel, a passageway in a coal mine, or thelike.

It is to be understood that the form of this invention herewith shownand described is to be taken as a preferred example of the same, and

that various changes in the shape, size, and ar-- rangement of parts maybe resorted to without departing from the spirit of the invention or thescope of the subioined claims.

Having thus described the inventiomwe claim:

1. A method of employing liquid carbon dioxide for extinguishing a fireinvolving an enclosure having an opening in a wall thereof, comprisingconducting liquid carbon dioxide to regions of release extending thelength of opposed margins of said opening, discharging said liquidthrough constricted orifices spaced at suitable intervals along each ofsaid regions to permit sudden expansion of the liquid to effect itsconversion into snow and vapors, maintaining in confinement the snow andvapors until the separate discharges of the same merge throughout thelength of each of said margins, causing the snow and vapors to partakeof curvilinear motion while thus confined so that the difference indensity of the snow and the vapors will effect segregation of thesecomponents, discharging a part of the segregated snow from both .of themargins into the interior of the enclosure, and discharging theremaining snow and the vapors from both of said margins toward eachother to form a screen or barrier across the entire area of saidopening.

2. A method of employing liquid carbon dioxide for extinguishing a fireinvolving an enclosure having an opening in a wall thereof, com prisingconducting liquid carbon dioxide to reglons of release extending thelength of opposed margins of said opening, discharging said liquidthrough constricted orifices spaced at suitable intervals along each ofsaid regions to permit sudden expansion of the liquid to effect itsconversion into streams of snow and vapors, uniformly'defiecting theflowing snow and vapor streams from their normal straight line paths ofmove-- referr d to in the r 'ment while allowing them to mergelengthwise.

of each of said margins, maintaining the flowing snow and vapors underthe influence of the force producing said deflection untiltheirdlfference in density effects a substantial segregation' of thesecomponents, discharging a part of the segregated snow from both of themargins into the interior of the enclosure, and discharging theremaining snow and the vapors from both of said margins toward eachother to form a screen or barrier across the entire area of the opening.

3. A method of employing liquid carbon dioxide for extinguishing a fireinvolving an enclosure having an opening in a wall thereof, comprisingconducting liquid carbon dioxide to regions of release extending thelength of opposed margins of said opening, discharging the liquid ateach of said regions through spaced constricted i orifices into. achamber that extends lengthwise ing through the chamber of said regionto permit sudden expansion of the liquid to 'eifect its conversion intosnow and vapors, causing the flowing snow and vapors tomerge throughoutthe length of each chamber and to partake of curvilinear motion-whileflowto effect substantial segregation of these components, discharging apart of the segregated snow from both of the margins into the interiorof the enclosure, and discharging the remaining snow and-the vapors fromboth of said margins toward each other to form a screen or barrieracrossthe entire area of said opening.

4. A method of employing liquid carbon dioxide for creating a screen orbarrier entirely across an open area and developing a fire extinguishingconcentration on one side thereof, comprising conducting liquid carbondioxide to regions of release arranged in a common plane andextendasaavsa ing the lengthoi omosite margins of saidarea,

, gins, causing the snow and vapors to partake of curvilinear motionwhile thus confined so that the difi'erence in density of the snow andvapors will effect segregation of these components, discharging a partoi the segregated snow from both of the margins to one side or the saidcommon plane of both of said regions, and discharging the remaining snowand the vapors from both of said margins toward each other to form ascreen or barrier entirely acrpss' said area and in said common plane.

5. A method of employing liquid carbon dioxide for creating a screen orbarrier entirely across an open area and developing a fire extinguishingconcentration on one side thereof, comprising conducting liquid carbondioxide to regions of release arranged in a common plane and extendingthe length of opposed margins of said area, discharging said liquidthrough constricted orifices spaced at suitable intervals along each ofsaid regions to pennit sudden expansion of the liquid to effect itsconversion into streams of snow and vapors, uniformly deflecting thenowing snow and vapor streams from their normal l straight line paths ofmovementwhile allowing them to merge lengthwise of each of said margins,maintaining the fiowlng snow and vapors under the influence of the forceproducing said deflection until their difierence in density effects asubstantial segregation of these components,

conducting liquid carbon dioxide to regions of release arranged in acommon plane and extending the length of opposed margins of said area,discharging the liquid at each of said regions through spacedconstricted orifices into a chamher that extends lengthwise of saidregion to permit sudden expansion of the liquid to eiiect its conversioninto snow and vapors, causing the flowing snow and vapors to mergethroughout the length of each chamber and to partake of curvilinearmotion while flowing through the chamber to eiiect substantialsegregation of these components, discharging a part ,of the segregatedsnow from both of the chambers to one side of the said common plane ofboth of said regions, and discharging the remaining snow and the vaparsfrom both of said chambers toward each other to form ascreen or barrierentirely across said area and in said common plane. I i

7. A method of employing liquid cabon dioxide for extinguishing a tireinvolving an enclosure having an opening in a wall thereof, comprisingconducting liquid carbon dioxide to regions of release extending thelengths of opposed margins of said opening, discharging said liquidthrough constricted orifices spaced at suitable intervals 515 along eachof said regions to permitsudden ex pansion oi the liquid to eflect itsconversion into snow and vapors. maintaining in confinement the snow andvapors until the separate discharges oi. the same merge throughout thelength of each of said margins, discharging a part of the carbon dioxidefrom both of the margin into the interior of the enclosure, anddischarging theremaining 'carbon dioxide from both 01 said marginstoward each other to form a screen or barrier across the entire area ofthe opening.

81 A method of employing liquid carbon dioxide for extinguishing afireinvolving an enclosure having an opening in a wall thereof, comprisingconducting liquid carbon dioxide to regions oi release extending thelengths of opposed margins of said opening, discharging said liquidthrough constricted orifices spaced at suitable intervals along each ofsaid regions to permit sudden expansion-ot the-liquid to effect itsconversion into streams of snow and vapors, permitting said flowing snowand vapor streams to' merge lengthwise of each of said margins into acontinuous mass equal in length to said margin, discharging a part ofthe carbon dioxide from both of the mar gins into the interior of theenclosure, and discharging the remaining carbon from'both or saidmargins toward each other to formfa screen or barrier across the entirearea of said opening.

9. A method of employing liquid carbon dioxide for extinguishing a'fireinvolving an enclosure having an opening in a wall thereof, comprisingconducting liquid carbon dioxide to regions of release extending thelengths of opposed margins of said opening, discharging the liquid ateach of said regions through spaced constricted orifices into a chamberthat extends lengthwise of said region to permit sudden expansion of theliquid to etfect its conversion into snow and vapors, causing thefiowing snow and vapors to merge lengthwise of each chamber, discharginga part of the carbon dioxide from both of the chambers into the interiorof the enclosure, and discharging the remaining carbon dioxide from bothoi the chambers toward each other to form a screen or barrier across theentire area of said opening.

10. A method of employing liquid carbon dioxide i'or creating a screenor barrier entirely across an open area and developing a fireextinguishing concentration on one side thereof, comprising conductingliquid carbon dioxide to regions of release arranged in a common planeand extending the lengths of opposed margins of said area, dischargingsaid liquid through constricted orifices spaced at suitable intervalsalong each of said regions 'to permit sudden expansion of the liquid toeffect its conversion into snow and vapors, maintaining in confinementthe snow and vapors until the separate discharges of the same mergethroughout the length of each 01 said margins, discharging a part of thecarbon dioxide from both or the margins to one side oi. the said commonplane 01' both of said regions, and discharging the remaining snow andvapors from both of the margins toward each other to form a screen orbarrier entirely across said area and in said common plane.

11. A method of employing liquid carbon dioxide tor extinguishing a fireinvolving an enclosure having an opening in a wall thereof, comprisingconducting liquid carbon dioxide to regions 01' release extending thelengths of opwposed margins of said opening, discharging said mit suddenexpansion or the liquid to erect its conversion into snow and vapors,maintaining in confinement the snow and vapors until the sepa- .ratedischarges of the same merge throughout the length 01' each oi saidmargins, causing the snow and vapors to partake oi curvilinear motionwhile'thus confined so that the diflerence in density of the snow andthe vapors will eflect se regation of thesecomponentsinto superimposedlayers, discharging a part of the snow layer from both of the marginsinto the interior of the enclosure. and discharging the vapor layer andthe remainder of the snow layer from both oi said margins toward eachother to form a screen or barrier across the entire area of said openingwith the snow layer arranged on the enclosure side of the screen orbarrier so as to be shielded from the atmosphere outside of theenclosure by the vapor layer.

12. A method 01' employing liquid carbon dioxide ior extinguishing afire involving an enclosure having an opening in a wall thereof,comprising conducting liquid carbon dioxide to regions of releaseextending the lengths oi opposed margins 01 said opening, dischargingsaid liquid through constricted orifices spaced at suitable intervalsalong each of said regions to permit sudden expansion or the liquid toeffect its conversion into streams of snow and vapors, uniiormlydeflecting the flowing snow and vapor streams from their normal straightline paths of movement while allowing them to merge lengthwise oi' eachof said margins, maintaining the flowing snow and vapors under theinfluence oi the force producing said deflection until their differencein density eflects a substantial segregation of these components intosuperimposed layers, discharging a part of the snow layer from both 01'the margins into the interior of the enclosure, and discharging thevapor layer and -'the remainder of the snow layer from both of saidmargins toward each other to form a screen or barrier across the entirearea or said opening with the snow layer arranged on the enclosure sideoithe screen or barrier so as to be shielded by the vapor layer from theatmosphere outside the enclosure.

x 13. A method of employing liquid carbon dioxide for extinguishing afire involving an enclosure having an opening in a wall thereof,comprising conducting liquid carbon dioxide to regions of releaseextending the lengths of opposed margins of said opening, dischargingthe liquid at each of said regions through spaced constricted orificesinto a chamber that extends lengthwise of said region to permit suddenexpansion or the liquid to efl'ect its conversion into snow and vapors,causing the flowing snow and vapors to merge throughout the length oreach chamber and to partake of curvilinear motion while new ing throughthe chamber to eflect substantial segregation of these components intosuperimposed layers, discharging a part of the snow layer from both ofthe chambers into the interior of the enclosure, and discharging thevapor layer and the remainder or the snow layer from both of saidchambers toward each other to form a screen or barrier across the entirearea of said opening with the snow layerarranged on the enclosure side01' the screen or barrier so as to be shielded by the vapor layer fromthe atmosphere outside the enclosure.

14. A method of employing liquid carbon dioxide for creating a screen orbarrier entirely across an open area and developing a fire extinguishingconcentration on one slde thereoi,

comprising conducting liquid carbon dioxide to regions or releasearranged in a common plane and extending the lengths of opposed marginsof said area, discharging said liquid through constricted orificesspaced at suitable intervals along each or said regions to permit suddenexpansion or the liquid to efl'ect its conversion into snow and vapors,maintaining in confinement the snow and vapors until the separatedischarges of the same merge throughout the length of each of saidmargins, causing the snow and vapors to partake of curvilinear motionwhile thus confined so that the difierence in density of the snow andvapors will efiect segregation oi,v these components into superimposedlayers, discharging a part 0! the snow layer from both of the marginsinto the interior of the enclosure, and discharging the vapor layer andthe remainder of the snow layer from both of said-margins toward eachother to form a screen or barrier across the entire area or said openingwith the snow layer arranged on the enclosure side 01' the screen orbarrier so as to be shielded by the vapor layer from the atmosphereoutside the enclosure.

I 15. A method of employing liquid carbon dioxide for extinguishing afire involving an enclosure having an opening in a wall thereof,comprising eflecting sudden release of the liquid along regionsextending the lengths of opposite margins of said opening to lower itspressure suificiently to form snow and vapors, eflecting segregation ofthe snow and vapors, discharging a part of the segregated snow from bothof said margins into the interior of the enclosure, and discharging fromboth 01' said margins the remaining segregated snow and the segregatedvapors as superimposed layers to form a screen or barrier across theentire area of said opening.

16. A method of employing liquid carbon dioxide ior extinguishing a flreinvolving an enclosure having an opening in a wall thereof, comprisingefiecting sudden release of the liquid along regions extending thelengths of opposite 1 margins of said opening to lower its pressuresufficiently to form snow and vapors-effecting segregation or the snowand vapors, discharging a part of the segregated snow from both of saidmargins into the interior of the enclosure, and discharging from both ofsaid margins the remaining segregated snow and the segregated vapors assuperimposed layers to form a screen or barrier across the entire areaof said opening with the snow layer arranged on the enclosure side ofthe screen or barrier so as to be shielded by the vapor layer from theatmosphere outside the enclosure.

17. A method of employing liquid carbon dioxide tor extinguishing a fireinvolving an enclosure having an opening in a wall thereof, comprisingeffecting sudden release of the liquid along regions extending thelengths of opposite margins of said opening to lower its pressuresufliciently to form snow and vapors, effecting segregation of the snowandyapors, discharging a part of the carbon dioxide from both of saidmargins into the interior '0! the enclosure, and discharging theremainder oi the carbon dioxide from both or the margins to form ascreen or barrier across the entire area of said opening.

18. Fire extinguishing apparatusior discharging liquid carbon dioxide toeflect extinguishment of a. fire involving an enclosure having anopening in a wall thereof, comprising a vertically elongated chamberextending the height 01' each her to form snow gatedvchamber extendingthe'length thereof, the wall oi'said sheaves of said side margins of theenclosure opening, each or said chambers havingv ay main dischargeopening extending thelength thereof and facing toward the otherof'saidchambers and a longitudinal series of secondary openings facing in- V'riphery from one wardiv oi said-enclosure, and a discharge pipeextendinglengthwise of each chamber and having a longitudinal series oforifices through which liquid carbon dioxide is released into thechamand vapors which will be discharged through said main and secondaryopen? kiss. 1

19. Fire extinguishing apparatus for discharging liquid carbon dioxide,comprising an elongated chamber having a main discharge openingextending thelength thereof and a longitudinal series of secondaryopenings facing at an angle to themaindischarge opening, and a dischargepipe extendinglengthwise of said chamber and having alongitudinalvseries oi orifices through which liquid carbon'dioxide isreleased into the chamber toiorm snow and vapors which will bedischarged through said main and secondary openingsnf 20. Fireextinguishing apparatus fordischargin: liquidcarbon dioxide, comprisingan elonhaving a main discharge opening chamber being curved throughoutits entire pemargin to the otherot said main discharge opening, saidchamber wall having a longitudinal series of tongues struck inwardlythereof to provide a series 01 secondary openings arranged adjacent toand parallel with one '0! the longitudinal margins of the main dischargeopening, and a discharge pipe extending lengthwise of the chamber andhaving a longitudinal series of oriilces through which liquid carbondioxide is released into the chamber to form snow and vapors, saidrelease orifices facing toward the curved wall 0! said chamber so thatthe snow and vapors will contact the latter adjacent the other of themarginal edges of said main discharge opening so that the snow andvapors will be caused to travel a curvilinear path while flowing fromthe orifices to the main discharge opening, said curvilinear motion orthe snow and vapors causing segregation oi these components as a resultof the more dense snow seeking apath oi flow adjacent the inner surfaceof the curved chamber wall, said series 0! tongues operating to deflectsome oi the segregated snow through the series of secondary openings.

BIL-DING V. WELIAMSON. WALTER F. MI'ICIEL'I'REE.

